The Machine to Machine (abbreviated as M2M) communication network is composed of various M2M nodes and the bearer network. The M2M nodes communicate with each other through the bearer network, and one M2M node at least includes: one application entity or one common service entity.
The application entity is a logic unit for executing the actual M2M application, and the common service entity is a logic unit for performing the management and service on the application.
In the M2M system architecture, the application node is an execution node at the end, such as, a smart meter, a temperature measurement and control sensor, a fire alarm, an intelligent home appliance, and so on, the intermediate node is a middleware for connecting the execution node at the end to a server at the network side, such as, a gateway, the basis node is the server the network side, and the application entity registered on the basis node usually is the management software or management platform of the M2M service provider.
The communication among the M2M applications is achieved through the interaction among the common service entities (CSE), while the premise of the communication is that the M2M applications first need to be registered in the local CSE, for example: the application entity on the application node needs to be registered in the CSE on the intermediate node, and the CSE node on the intermediate node is the local CSE of the application entity on the application node, and then the interaction among the M2M applications is achieved through the communication among the CSEs, as the M2M system architecture diagram shown in FIG. 1, including: an application node, an intermediate node, and a basis node. herein,
the application node is a physical entity, and the application entity (AE) is a logical unit, which is a logical unit that really executes the application on the application node which is the physical entity.
When the AE is registered in the local CSE, the AE needs to provide a security certificate that can identify its own legitimacy to the local CSE for verification, and it can be registered in the local CSE only when the verification is passed, and the AE further needs to provide the registered name suggested by the AE to the local CSE for reference.
The AE after registration can also create resources related to the applications on the local CSE, as the sub-resources of the application resources, for example: the AE after registration creates the resource “application” on the local CSE, in order to store the data of the application, the AE can also create a resource “container” under the resource “application”, and the resource “container” is used to store the data related to the AE. The AE can acquire a message that indicates whether a certain resource is changed in the subscription mode. When the attribute or sub-resource of the subscripted resource is changed, for example, the attribute value is modified, the sub-resource is deleted, or a new sub-resource is created, etc., the CSE where the subscripted resource is located can send a notification message to the AE, to inform that the subscription resource has been modified.
The subscription to the resource is achieved by the AE creating the sub-resource of which the type is “subscription” under the resource of the CSE. The resources subscripted by the AE may contain more attributes and sub-resources, so the subscripted resources may be frequently modified, and the notification message will be sent to the AE at every modification according to the subscription rules of the existing technology, and thus resulting that a large number of notification messages are brought and stored on the CSE.